marines in afghanistan. when his unit went on patrol january 15th. >> pretty much plain and simple, somebody was going to get hit that day. that somebody was me. >> reporter: he was hit by an ied. >> just went inside a compound, they found a cache. that was good for us. i guess that area wasn't secured, so -- >> reporter: he's a triple ambu tee. but ophthalmologists are worried he could worry his sight. he says explosions that cause brain injuries off cause eye injuries. >> if they were near blasts and lost consciousness, they would be at risk. >> reporter: this is no small problem. the defense and veterans brain injury center says at least 212,000 veterans have brain injuries and they all need this specialized eye exam. dr. cokerham says he is focused on getting vets examined. a closer look with a tool can reveal dangerous internal injuries. >> as the eye is compressed from the blast wave, this is the part in the eye that tears most easily. we can look in there and see scarring for the rest of their lives i